Screw-hole liner



March 11, 1952 M. MARKS 2,588,860

SCREW-HOLE LINER Filed Feb. 12, 1948 'INVENTOR.

Patented Mar. 11, 1952 UNITED STATES PATENT OFFICE This invention relates to screw-holders and,

more inparticular, to metallic screw-hole liners for anchoring screws in their holes.

It is known that when screws have been embedded in wood, in order to secure in position some element such as a drawer-knob or the like, they tend to work loose or can be torn loose because their metalthreads can rip through the wood fibers. To avoid this, metal screw-hole liners .have been inserted in pre-formed screwholes prior to the threading-in of the screws, the theory being that the engagement of the screw threads with the metal of the liner will prevent the screw from being torn loose. However, these liners, or screw-holders are subject to a number of objectionsone such being that they are expensive' to manufacture and therefore'not commercially practicable. Also, they are difficult to fit into the screw-holes and a diiferent sized liner must be provided for holes of slightly varying diameter. Further, the liners themselves do not become firmly embedded 'in the hole-walls and,

I consequently, can be pulled out along with the screws, one reason for this being that, as the simple and inexpensive to manufacture, which is.

easily insertable in a screw-hole and can be used for holes of varying diameters, and which will securely anchor a screw in place.

The holder provided according to this invention is fabricated from thin-Walled, easily workable sheet metal which readily yields to quick and inexpensive manufacturing operations. The major portion of the holder is arcuately curved so as to conform to the curvature of a screw and has outwardly pressed threads formed on it. Preferably, the side edges of this portion are straight edges and the threads are formed between them, while at the front end of the holder, there is formed an outwardly projecting barb or prong. The holder is manually placed in the screw-hole and the screw then inserted. If the hole is found to be smaller than the holder, the holder can compress to fit it. This is possible since the holder is slit longitudinally from its front end throughout a major portion of its length, the slit forming a space for compressing the side arms. Also, at the front end of the side arms are formed laterally projecting, rearwardlytapering pointed wings which. as the holder enters its screw-hole, bear against the sides of the hole and cause the side arms to compress. In

1 Claim. (c1.'1 51 14) 2 effect, the wings provide a cam surface for the compression.

As the screw is being worked in, the barb of the holder, the pointed wings, and the straight side edges or the rear portion dig into the wall of thescrew-hole and prevent rotation of the holder with the screw. In manufacture, the holders are made from a strip of metal which is advanced through a series of stations that successively slit, shape, bend and finally slice the finished holder from the strip. By this manufacturing process the holders can be rapidly produced at very small cost.

The invention is illustrated in the accompanying drawings in which Fig. 1 is a plan view of a blank. for forming one form of the holder; Figs. 2, 3 and 4 are, respectively, plan, side and perspective views of the same holder after bendingf Figs. 5, 6 and 7 are, respectively, side, plan and perspective views of another form of the invention; Fig. 8 is'a sectional view showing a screw and holder positioned in a screw-hole; and Fig. 9 shows a holder entering a screw-hole.

Referring to Figs. 2 to 4, the holder there illustrated, is arcuately curved into a segment of a cylinder, and, along its rear portion 1, are formed outwardly pressed transverse threads 2 which,

however, do not extend the full width so that the side edgesof this portion are straight instead of being threaded. Further, it is preferable, to bend each side edge into a laterally extending flange 3 (Fig. 4).

As shown in Fig. 1, prior to any bending, the holder is generally arrow-shaped and is divided by slits :l and 5 into a central tongue member 6 and side members i and 8. As seen, the slits run first inwardly at the front end of the holder and then rearwardly, thereby forming, on the central tongue member, projecting flanges 9 and it. In a subsequent operation, these flanges are bent outwardly along lines II and I2 to form a pair of pointed barbs l3 and [4 (Figs. 3 and 4), the purpose of which will be explained later. Side members I and 8 also are specially shaped to provide wings l6 and II which project laterally beyond the width of the rear portion of the holder. The sides of these wings taper outwardly from the front of the side members to form what may be called cam surfaces I8 and [9. As shown in Fig. 4, these wings are not bent arcuately with the rest of the holder so that, in the finished holder, they still project in a lateral direction.

In use, the holder first is inserted manually in a screw-hole and then the screw worked in. As illustrated in Fig. 9, it often will be found that the screw-hole is smaller than the holder. In such a case, as the holder enters the hole, the cam surfaces 18 and I9 of the holders wings strike the edge of the hole and, as the holder is pressed downwardly, side members I and 8 are pressed toward each other and the holder compressed into a size which will fit into the hole. Also, barbs l3 and M strike the holes edge and aid in compressing the holder to proper size. When the threading-in ofthesorew is begun, barbs l3 and M will be'pressed into the wall of .the iholeand will resist any tendency of the holder to rotate with the screw. Also, pointed wings l6 and "I1 and flanges 3 at the holders rear portion, will di into the wall of' the hole and further'resist'the tendency to rotate. l

After the screw has been worked in .the full distance, it is firmly anchored due to the fact that the threads of the screw have forced the metal threads of the holder into the hole wall a .to securely embed them therein, and the threads of the screw are engaged by the metal of the holder. Any force tending to rip .the screw "from its hole is resisted by this engagement and also 'by the fact thatbarbs l3 and M are embedded in the wall of the hole.

Another form of the invention is illustrated in Figs. 5, 6 and 7. The principal differencein this form is that, in place .of being slit to permit compression, it isprovided with a rearwardly extendingnotched or cut-away portion 26 which divides the holder into side arms Z'lanclZB. Also barbs I3 and it are formed by bending the tips of the side arms downwardly. Asideffrom that, this holder is the same as that previously described, it having a threaded rear portion on which are formed straight edged flanges 3 and, also, wings l6 and I1, which have tapering cam edges is and 9 for compressing the holder into a suitable size for a hole. Further, it will be understood that this form functions in the same 7 manner as that previously described. The many advantages of holdersofthis type should be readily apparent. They are easily insertable .iniholes of different diameters, unusually efiicient in anchoring a screw in placeand can be manufactured very simply-and inexpensively so that they are' a practical commercial item. They are particularly economic in maintenance and repair work in that they permit the .old screws and screw-holes .t

r be used any numberofltimes.

said body having sections of outwardly pressed screw-receiving threads extending across it, the central portion of said body being provided with a pair of laterally spaced slits extending from itsfront end rearwardly throughout a major portion of its length to form a central flexible tongue between a pair of flexible side arms, the tongue projecting ahead of the side arms and having the opposite edges of its, projecting portion provided with integral barbs projecting away from the convex side of the body'for engagement with-the wall of a screw-holeto prevent rotation of "the holder therein, and the front edgesof'gtheside armsbeing inclined rearwardly' from the tongue to the side edges of said bodyto form cam-surfaces for pressing the arms toward'eachaother when the holder is driven into an undersize screw-hole.

MILTON REFERENCES CITED The following references are of record in .the

flle of this patent:

UNITED STATES PATENTS jNumber Name 7 Date 1,114,971 Diefendorf Oct. 27,1914 1,286,285 Girvan Dec: 3,1918 1,396,569 Girvan NOVq8, 1921 1,434,806 Brown -Nov. 7,-1-921 FOREIGN PATENTS Number Country .Date

222,047 Great Britain -JSept. 25,1924

GreatBritain Nov. 16,1906 

